This invention relates to a propeller assembly for use generally in watercraft, and in particular to such a propeller assembly the pitch of the blades of which is variable and controllable by use of stationary power cylinders connected to the rotating blades.
In general, of course, variable pitch propeller assemblies for watercraft are quite well known in the art. The majority of them, however, have been lever-driven. For example, Muller, U.S. Pat. No. 4,599,043, shows a device for changing the pitch of a propeller in a watercraft, in which the change is accomplished by use of a lever at the outflow side of the propeller, which lever is remotely controlled by a hydraulic cylinder. That patent states that the lever may be moved to the inflow side, without explaining how such a transformation is possible. In another example, Muller, U.S. Pat. No. 4,744,727, such a lever is shown positioned at the inflow side of the propeller. However, external levers such as the ones shown in the Muller and Muller patents have the disadvantage of disrupting the water flow around the propeller, providing means for catching weeds, and so on. On the other hand, MacFarland, U.S. Pat. No. 3,056,457, shows a variable pitch propeller wherein the change in pitch is powered by internal hydraulic cylinders and springs. This structure is somewhat complex, however, and it appears that it would be quite expensive to manufacture.
This invention relates to improvements to the apparatus described above and to solutions to the problems raised thereby.